ignore invalid accept header values instead of throwing an error

[elikoga]

Please don't delete this checklist! Before submitting the PR, please make sure you do the following:

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
  • closes Accept header parsing possibly too strict #4962
• This message body should clearly illustrate what problems it solves.
  • User encountered clients sending invalid accept header values in the wild, resulting in 500 error codes in logs.
• Ideally, include a test that fails without this PR but passes with it.

Tests

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  • minor change, so I don't think this needs a changelog

[changeset-bot]

🦋 Changeset detected

Latest commit: c66fa25

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@sveltejs/kit	Patch

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[Rich-Harris]

thank you — can we use map instead of flatMap? feels slightly circuitous to create extra arrays only to unwrap them. made suggestions in the relevant places

[Rich-Harris]

thank you!